Several normally wheeled vehicles and particularly heavy wheeled vehicles (e.g. farming tractors, front loaders, harvesters, etc.) often have their wheels replaced by track systems which use an endless traction band instead of a tire for propulsion. Vehicles equipped with track systems typically have improved floatation and traction, particularly when they are operated over soft terrains.
However, during operation, some components of the track systems, and more particularly the idler wheels and road wheels, can experience uneven load distribution. This is particularly true when the idler wheels and the road wheels are mounted in tandem on tandem frames.
Indeed, in such track systems, the resultant force from the traction band tension and the traction band friction can induce a torque around the tandem frame pivot, resulting in the rotation of the tandem frame thereabout. This rotation then generally causes the wheels located at one end of the tandem frame to move upwardly while causing the wheels located at the other end of the tandem frame to move downwardly, resulting in an increased load on the wheels which are urged downwardly. The rotation of the tandem frame can also cause the trailing portion of the track system to rise. This uneven load distribution can reduce the efficiency of the track system and even lead to premature failure thereof.
Furthermore, when the vehicle equipped with such track systems needs to frequently switch from moving in a forward direction to moving in a rearward direction, and vice-versa, there is often an unpleasant lag time before the track systems properly respond to the change in moving direction. This lag time is at least partially caused by the time it takes for the tandem frames to pivot back to their normal position and then to their new pivoted position. This lag time causes, among other things, unwanted delays in the operation of the vehicle.
Hence, there is a need for an improved track system which mitigates at least some shortcomings of prior art track systems.